Nonresonant multiphoton ionization of rare gases

For the purpose of applying the laser-ionization method to measuring gas pressure, the dependence of the ionization output signals of rare gases on the gas pressure and the laser intensity were studied using XeCl, KrF, and ArF excimer lasers. The proportional relation between the ionization signal and the gas pressure was experimentally verified to below 10 ⁸ Torr. In the case of Kr gas, the dependence of the ionization signal on the laser intensity was in agreement with the theory of nonresonant multiphoton ionization, and saturation of ionization in the case of Xe was observed.